Transglutaminase is an enzyme which catalyzes an acyl transfer reaction of a γ-carboxy amide group of glutamine residue in a peptide chain. In particular, transglutaminase induces intramolecular or intermolecular formation of e-(γ-Gln)-Lys cross linking to an e-amino group of a lysine residue in a protein. The enzyme has been widely used for processing proteins by using this property in the fields of food and medicine.
Since a long time ago, animal-derived transglutaminase has been known. It has been reported that transglutaminase has been found in animals, for example, in the liver of guinea pigs and in organs and blood of mammals (Connellan et al., Journal of Biological Chemistry, vol. 246, No. 4, pp. 1093-1098 (1971)), Folk et al., Advances in Enzymology, vol. 38, pp. 109-191 (1973); and Folk et al., Advances in Protein Chemistry, vol. 31, pp. 1-133 (1977)), and its enzymological properties have been studied. On the other hand, a different type of transglutaminase, which is not dependent upon calcium (Ca2+) and is therefore different from the above-mentioned animal-derived transglutaminase, has been found. Specifically, transglutaminase has been isolated and identified from Streptomyces mobaraensis [old name: Streptoverticillium mobaraense] IFO 13819 (Japanese Patent Unexamined Publication No. S64-27471), Streptomyces griseocarneus [old name: Streptoverticillium griseocarneum)] IFO 12776, and Streptomyces cinnamoneus) [old name: Streptoverticillium cinnamoneum)] IFO 12852 (Japanese Patent Unexamined Publication No. 2001-186884), etc.